scholarly journals Siciak–Zahariuta extremal functions, analytic discs and polynomial hulls

2009 ◽  
Vol 345 (1) ◽  
pp. 159-174 ◽  
Author(s):  
Finnur Lárusson ◽  
Ragnar Sigurdsson
2017 ◽  
Vol 145 (10) ◽  
pp. 4443-4448
Author(s):  
Egmont Porten

2019 ◽  
Vol 378 (3-4) ◽  
pp. 829-852
Author(s):  
Alexander J. Izzo

2007 ◽  
Vol 91 (2-3) ◽  
pp. 235-239 ◽  
Author(s):  
Finnur Lárusson ◽  
Ragnar Sigurdsson

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1108
Author(s):  
Olga Kudryavtseva ◽  
Aleksei Solodov

The class of holomorphic self-maps of a disk with a boundary fixed point is studied. For this class of functions, the famous Julia–Carathéodory theorem gives a sharp estimate of the angular derivative at the boundary fixed point in terms of the image of the interior point. In the case when additional information about the value of the derivative at the interior point is known, a sharp estimate of the angular derivative at the boundary fixed point is obtained. As a consequence, the sharpness of the boundary Dieudonné–Pick lemma is established and the class of the extremal functions is identified. An unimprovable strengthening of the Osserman general boundary lemma is also obtained.


2021 ◽  
Vol 27 (3) ◽  
Author(s):  
Paweł Zaprawa

AbstractIn this paper, we obtain the bounds of the initial logarithmic coefficients for functions in the classes $${\mathcal {S}}_S^*$$ S S ∗ and $${\mathcal {K}}_S$$ K S of functions which are starlike with respect to symmetric points and convex with respect to symmetric points, respectively. In our research, we use a different approach than the usual one in which the coeffcients of f are expressed by the corresponding coeffcients of functions with positive real part. In what follows, we express the coeffcients of f in $${\mathcal {S}}_S^*$$ S S ∗ and $${\mathcal {K}}_S$$ K S by the corresponding coeffcients of Schwarz functions. In the proofs, we apply some inequalities for these functions obtained by Prokhorov and Szynal, by Carlson and by Efraimidis. This approach offers a additional benefit. In many cases, it is easily possible to predict the exact result and to select extremal functions. It is the case for $${\mathcal {S}}_S^*$$ S S ∗ and $${\mathcal {K}}_S$$ K S .


2000 ◽  
Vol 317 (4) ◽  
pp. 677-701 ◽  
Author(s):  
Marshall A. Whittlesey
Keyword(s):  

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